This invention relates to an ocular device which can be surgically associated with, e.g., surgically implanted into, a living cornea or, in another embodiment, is suitable for being located in proximity to a damaged, living cornea. More particularly, the invention relates to such ocular devices which promote at least one of the growth and adhesion of the living cornea, e.g., corneal epithelium, onto the ocular device after surgery and act to correct a vision problem or, which promote the healing of the damaged cornea and may act to correct a vision problem, e.g., a refractive error.
The cornea comprises five layers, including an outer layer of epithelial cells, Bowman's membrane immediately posterior of the cells, the stroma immediately posterior of Bowman's membrane, Descemet's membrane immediately posterior of the stroma and the endothelium immediately posterior of Descemet's membrane. A number of surgical operations involve implanting a corrective lens structure into or onto one or more of these corneal components. For example, in one form of eye surgery, the layer of epithelial cells is removed and a corrective lens structure is placed and secured at the location where the cells were removed. In another form of eye surgery, a portion of the layer of epithelial cells is removed and then a wedge-shaped annulus from Bowman's membrane and the underlying stroma is removed. An incision is then made from the posterior end of the resulting groove radially outwardly in an annular zone to define a flap. A corrective lens structure is attached by inserting the wing of the lens structure beneath the corneal flap and fixing, e.g., suturing, it in place. In addition, a corrective lens structure can be placed entirely within the stroma. This surgical procedure involves making an incision in the cornea to gain access to the stroma and also involves disrupting the stroma by placing a lens structure therein.
In each of these surgical procedures, it is highly desirable, even necessary, for the long term viability of such lens onlays or implants that the cornea, e.g., the epithelial cells, grow onto the lens structure and/or adhere to the lens structure. Achieving such growth and adhesion has been one substantial problem inhibiting the use of such corneal onlay and implant procedures.
One suggestion to overcome this problem has been to add drops of liquid fibronectin solution to the cornea after surgery to enhance the growth of the epithelial cells. However, this approach has not proven to be totally successful. For example, the drops must be added to the eye very frequently. This is troublesome and may lead to discomfort. Even with the frequent addition of drops, it is very difficult to have an effective amount of the fibronectin present. The natural cleansing action, e.g., tearing action, of the eye tends to eliminate the fibronectin.
Another situation which often occurs is that the cornea becomes damaged, e.g., in sports-related incidents and other accidents. Since such damage may cause relatively great discomfort and/or adversely affect one's vision, it is very desirable to heal the damage as soon as possible.